Light pollution has spread to the outskirts of the city, with hundreds of residents complaining about glare from excessive advertising lighting at a recently renovated shopping mall in Tseung Kwan O.

Residents of Yan Ming Court have been doing everything they can to block the light from the signs on the Metro City shopping mall, which faces the residential block.

Some have been keeping their curtains closed, and one resident has taken the extra step of placing a board next to his bed to block the light that still manages to seep through.

Local politicians and representatives of the green group Friends of the Earth have received numerous complaints since September last year, when the mall placed 12 brightly lit sign boards, each measuring about five storeys, around the mall.

The new fixtures replaced a collection of advertising banners that had been illuminated by spotlights.

When the mall was trying to find clients to rent the boards, the lights were left on until midnight. The mall eventually decided to switch them off at 11pm, but residents still found the glare too bright and wasteful.

“Some of the boards are located in places where few shoppers pass by,” Sai Kung district councillor Ng Ping-yiu said. “No one would ever look up at the boards when they are walking under them. The only audience is the residents who have to live facing them.”

Mr Ng said complaints had been filed with the Environmental Protection Department, though little could be done because there were no laws governing such lighting.

After repeated complaints, Henderson Land Development, which owns the mall, agreed to switch off the boards at 10.30pm. It also said it would consider decreasing the intensity of the light, though no changes have been made.

Mr Ng said he was worried that other malls in the district might adopt the mall’s lighting system as competition for shoppers intensified. He said he was hoping that a system for consultations and stakeholder meetings could be set up so residents and developers would have a chance to talk whenever new signage was being planned.

Cheng Sze-ling, environment affairs officer of Friends of the Earth, said the problem of light pollution was no longer restricted to developed and commercial areas such as Mong Kok or Causeway Bay; it had spread to residential areas in new towns. “Light pollution is no longer endemic but has evolved into an infectious disease across the city,” she said.

The group would organise a seminar for local politicians to help them understand light pollution and ways of handling it, she said. It would also publish a guide on the subject.

In response to press inquiries, a spokeswoman for Henderson Land Development said the company had studied dimming the glare by cutting the number of lights and would follow up on the findings shortly.

A spokesman for the Environmental Protection Department said the department had received eight complaints regarding light nuisances relating to Metro City mall. He said officials had been sent to the scene and had spoken to the mall’s owner to minimise nuisances.

“We have encouraged them to adhere to this arrangement and to consider using lamps that were less bright,” he said.